EVALUATING HISTORICAL AND FUTURE HYDROGEOLOGIC RESPONSE TO PUMPING AND INJECTION IN SUPPORT OF IN-SITU BITUMEN RECOVERY IN ALBERTA CANADA

There is reported to be 170 billion barrels of remaining established bitumen reserves in Alberta, Canada, with an ultimate potential (recoverable) of 315 billion barrels. Bitumen saturated sediments greater than 75 meters below ground surface are generally considered too deep for surface mining. Due to the high viscosity of the bitumen, exploitation of these deposits in-situ requires enhanced recovery methods, the most common being steam assisted gravity drainage. Steam assisted gravity drainage involves the injection of high temperature steam into the subsurface to decrease the viscosity of the bitumen and facilitate recovery. Although the vast majority of injected steam is recycled, most projects rely on groundwater as a source of steam generation make-up water. The projects also require suitable formations for wastewater disposal.

Given the high density of planned steam assisted gravity drainage projects in northeast Alberta, there is a high potential for groundwater resources becoming a source of conflict between producers. A detailed review of geology, operational history, and pressure response, was completed for three established oil sands producers in the area with the aim of avoiding potential conflicts by developing a common hydrogeologic framework and understanding. The work identified and delineated key regional aquifers and aquitards from ground surface to a depth of greater than 500 meters below ground surface. An abundance of geologic data was available from a shared database of geologic picks derived from downhole wireline logs. Hydrogeologic characteristics were evaluated by reviewing 7 years of groundwater pumping and wastewater injection history and the resulting transient pressure responses at 54 vibrating wire piezometers. The data were compiled and evaluated with a regional scale numerical model and the use of non-linear parameter estimation software. The process of developing a technical consensus between multiple clients provided many lessons that will facilitate communication and consensus building for future work.